An analysis of the NLRB's rulings also indicates that if an employee makes a comment on Facebook and fellow employees respond, it is considered protected activity. It is not protected, however, if only friends respond to the posting.

Employers' social media policies should not prohibit activity protected by federal labor law, but employees' comments generally are not protected if they are mere gripes, the National Labor Relations Board said Wednesday.

The comments accompanied a second report by Lafe E. Solomon, the NLRB's acting general counsel, describing social media cases reviewed by his office.The NLRB said the latest report underscores two main points made in the earlier report issued last August: "Employer policies should not be so sweeping that they prohibit the kinds of activity protected by federal labor law, such as the discussion of wages or working conditions among employees." However, "an employee's comments on social media are generally not protected if they are mere gripes not made in relation to group activity among employees," the NLRB said.

The NLRB said of the 14 cases covered in its Jan. 25 report, half involve questions about employer social media policy. Five were found to be unlawfully broad, one was found to be lawful and one was found to be lawful after it was revised.

The remaining cases involved discharge of employees after they posted comments on Facebook.

"Several of these were found to be unlawful because they flowed from unlawful policies," the NLRB said. In one case, though, the discharge was upheld despite an unlawful policy because the employee's posting was not work-related, the NLRB said.

Commenting on the conclusions, Doreen S. Davis, co-chair of the traditional labor practice at law firm Morgan, Lewis & Bockius L.L.P., said all the cases discussed in the latest report focus on two issues: whether the employer's social media policy was too broad and whether the disciplinary action taken was lawful.

"The immediate lesson for employers" is their social media policies should be reviewed, because statements in them such as "Employees may not make disparaging remarks about the company" or "Communications should at all times be professional" are going to be found to be overbroad and considered as prohibiting protected activity, Davis said.

An analysis of the NLRB's rulings also indicates that if an employee makes a comment on Facebook and fellow employees respond, it is considered protected activity. It is not protected, however, if only friends respond to the posting, Davis said.

She said with its attention to social media issues, the NLRB is seeking to become more relevant at a time when 93 percent of workplaces in the private sector are nonunionized. "It's an effort by the NLRB to reach out to nonunion employees to tell them they also have protections under the NLRB," she said.